The level of radioactivity on the site of a nuclear explosion is decaying exponentially. The level measured in 1970 was found to be 0.7 times the level measured in 1960. What is the half-life. (the amount of years)

Nov 6th 2007, 11:59 PM

janvdl

Radioactivity in 1970 =

Radioactivity in 1960 =

But

[Divide by y]

I think this is the rate at which it is decaying. I'll spend a little more time on it... :D